Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: Color Mixing (Pigment) question



The simple answer is that the book is incorrect.

Your ideas are correct.

The book is evidently confusing additive (light) color mixing and
subtractive (pigment) color mixing. If you mix green and blue light, then
the result is cyan light. If you mix green and blue pigments, you end up
with a black color.

This is true for the idealized colors we generally consider in physics
classes.

The real situation is more complex than that and involves whether the
pigments are transparent or opaque, spherical or flat, as well as the exact
absorption spectra of real pigments.

For some references:
<http://www.sci-ed-ga.org/modules/materialscience/color/sites.html>

For some other examples of misleading/confusing statements on color that are
rampant:
<http://www.sci-ed-ga.org/pdfs/primary_clrs.pdf>

Larry Woolf
General Atomics
3550 General Atomics Court
Mail Stop 78-110
San Diego CA 92121
Ph:858-526-8575
FAX:858-526-8568
http://www.ga.com
http://www.sci-ed-ga.org


-----Original Message-----
From: Forum for Physics Educators
Sent: 5/19/2004 10:11 AM
Subject: Color Mixing (Pigment) question

Our physics book (h.s.) had a question about what color is obtained when
pure green and pure blue pigment are mixed. The book answer was "cyan
pigment." Can someone explain this please?

Why is the result not black? The blue pigment filters out red & green
light and the green pigment filters out blue & red light, so why isn't
the result black?